Insight into Pseudomonas aeruginosa pyocyanin production under low-shear modeled microgravity
Long-term space flight impairs the immune system of astronauts, rendering them vulnerable to opportunistic infections. Pseudomonas aeruginosa causes opportunistic infections, particularly in individuals with a compromised immune system; it can be a major health hazard for astronauts during space flight missions. Hence, the production of the most abundant redox active virulence factor, pyocyanin by P. aeruginosa, was assessed under low-shear modeled microgravity (LSMMG) conditions, simulated using a high aspect ratio vessel. Moreover, we evaluated changes in the expression of genes involved in pyocyanin biosynthesis and genes involved in the MexGHI-OpmD operon quorum sensing. Extracellular DNA and H2O2 production were measured, and their correlation with pyocyanin production was examined. Interestingly, the pyocyanin quantity was 2.58-fold lower in the LSMMG conditions compared to the normal gravity. LSMMG caused downregulation of the genes associated with pyocyanin biosynthesis. Interestingly, extracellular DNA and H2O2 release were significantly high in the normal gravity environment. Scanning electron microscopy revealed aggregation and elongated cells under LSMMG. Taken together, these findings suggest that LSMMG did not induce pyocyanin secretion in P. aeruginosa.
KeywordsLow-shear modeled microgravity Pyocyanin Pseudomonas aeruginosa
The SEM samples were analyzed using the JEM-2010 (JEOL) installed at the Center for University-Wide Research Facilities (CURF) at Chonbuk National University. We thank Mrs. Eun-Jin Choi at the CURF at Chonbuk National University for SEM analysis.
This research was supported by Buan RIS Resource Project (Grand no. R0001102) and funds of Chonbuk National University.
Compliance with ethical standards
Conflict of interest
Authors do not have any conflicts of interest.
- 1.Iglewski BH (1996) Pseudomonas. In: Baron S (ed) Medical microbiology, 4th edn. University of Texas Medical Branch at Galveston, GalvestonGoogle Scholar
- 8.Bruce RJ, Ott CM, Skuratov VM, Pierson DL (2005) Microbial surveillance of potable water sources of the International Space Station. SAE Technical PaperGoogle Scholar
- 9.Reidt U, Halwig A, Muller G, Plobner L, Lugmayr V, Kharin S, Smirnov Y, Novikova N, Lenic J, Fetter V (2017) Detection of microorganisms onboard the international space station using an electronic nose. Gravit Space Res 5:89–111Google Scholar
- 13.Rai B, Kaur J, Catalina M (2010) Bone mineral density, bone mineral content, gingival crevicular fluid (matrix metalloproteinases. cathepsin K, osteocalcin), and salivary and serum osteocalcin levels in human mandible and alveolar bone under conditions of simulated microgravity. J Oral Sci 52:385–390CrossRefPubMedGoogle Scholar
- 16.Crabbé A, Schurr MJ, Monsieurs P, Morici L, Schurr J, Wilson JW, Ott CM, Tsaprailis G, Pierson DL, Stefanyshyn-Piper H (2011) Transcriptional and proteomic responses of Pseudomonas aeruginosa PAO1 to spaceflight conditions involve Hfq regulation and reveal a role for oxygen. Appl Environ Microbiol 77:1221–1230CrossRefPubMedGoogle Scholar
- 21.Crabbé A, Ledesma MA, Ott CM, Nickerson CA (2016) Response of Pseudomonas aeruginosa to spaceflight and spaceflight analogue culture: implications for astronaut health and the clinic. Effect of spaceflight and spaceflight analogue culture on human and microbial cells. Springer, BerlinGoogle Scholar
- 27.Nowroozi J, Sepahi AA, Rashnonejad A (2012) Pyocyanine biosynthetic genes in clinical and environmental isolates of Pseudomonas aeruginosa and detection of pyocyanine’s antimicrobial effects with or without colloidal silver nanoparticles. Cell J (Yakhteh) 14:7Google Scholar
- 31.Palma M, Zurita J, Ferreras JA, Worgall S, Larone DH, Shi L, Campagne F, Quadri LE (2005) Pseudomonas aeruginosa SoxR does not conform to the archetypal paradigm for SoxR-dependent regulation of the bacterial oxidative stress adaptive response. Infect Immun 73:2958–2966CrossRefPubMedPubMedCentralGoogle Scholar
- 32.Aendekerk S, Diggle SP, Song Z, Høiby N, Cornelis P, Williams P, Camara M (2005) The MexGHI-OpmD multidrug efflux pump controls growth, antibiotic susceptibility and virulence in Pseudomonas aeruginosa via 4-quinolone-dependent cell-to-cell communication. Microbiology 151:1113–1125CrossRefPubMedGoogle Scholar
- 40.Abshire CF, Prasai K, Soto I, Shi R, Concha M, Baddoo M, Flemington EK, Ennis DG, Scott RS, Harrison L (2016) Exposure of Mycobacterium marinum to low-shear modeled microgravity: effect on growth, the transcriptome and survival under stress. NPJ Microgravity 2:16038CrossRefPubMedPubMedCentralGoogle Scholar